<html>
<head>
<script type="text/javascript">
function Show(IDS,flag) {
  document.getElementById(IDS).style.display = flag;
}
</script>
</head>
<body>
<button onClick="Show('divTag','block')">+</button>
<button onClick="Show('divTag','none')">-</button>
<div id="divTag" style="display:none"> pressed </div>
</body>
</html>